linux-stable/drivers/spi/spi-bitbang.c

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treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157 Based on 3 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version [author] [kishon] [vijay] [abraham] [i] [kishon]@[ti] [com] this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version [author] [graeme] [gregory] [gg]@[slimlogic] [co] [uk] [author] [kishon] [vijay] [abraham] [i] [kishon]@[ti] [com] [based] [on] [twl6030]_[usb] [c] [author] [hema] [hk] [hemahk]@[ti] [com] this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 1105 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Richard Fontana <rfontana@redhat.com> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070033.202006027@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-27 06:55:06 +00:00
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* polling/bitbanging SPI master controller driver utilities
*/
#include <linux/spinlock.h>
#include <linux/workqueue.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/platform_device.h>
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 08:04:11 +00:00
#include <linux/slab.h>
#include <linux/spi/spi.h>
#include <linux/spi/spi_bitbang.h>
#define SPI_BITBANG_CS_DELAY 100
/*----------------------------------------------------------------------*/
/*
* FIRST PART (OPTIONAL): word-at-a-time spi_transfer support.
* Use this for GPIO or shift-register level hardware APIs.
*
* spi_bitbang_cs is in spi_device->controller_state, which is unavailable
* to glue code. These bitbang setup() and cleanup() routines are always
* used, though maybe they're called from controller-aware code.
*
* chipselect() and friends may use spi_device->controller_data and
* controller registers as appropriate.
*
*
* NOTE: SPI controller pins can often be used as GPIO pins instead,
* which means you could use a bitbang driver either to get hardware
* working quickly, or testing for differences that aren't speed related.
*/
struct spi_bitbang_cs {
unsigned nsecs; /* (clock cycle time)/2 */
u32 (*txrx_word)(struct spi_device *spi, unsigned nsecs,
u32 word, u8 bits, unsigned flags);
unsigned (*txrx_bufs)(struct spi_device *,
u32 (*txrx_word)(
struct spi_device *spi,
unsigned nsecs,
u32 word, u8 bits,
unsigned flags),
unsigned, struct spi_transfer *,
unsigned);
};
static unsigned bitbang_txrx_8(
struct spi_device *spi,
u32 (*txrx_word)(struct spi_device *spi,
unsigned nsecs,
u32 word, u8 bits,
unsigned flags),
unsigned ns,
struct spi_transfer *t,
unsigned flags
)
{
unsigned bits = t->bits_per_word;
unsigned count = t->len;
const u8 *tx = t->tx_buf;
u8 *rx = t->rx_buf;
while (likely(count > 0)) {
u8 word = 0;
if (tx)
word = *tx++;
word = txrx_word(spi, ns, word, bits, flags);
if (rx)
*rx++ = word;
count -= 1;
}
return t->len - count;
}
static unsigned bitbang_txrx_16(
struct spi_device *spi,
u32 (*txrx_word)(struct spi_device *spi,
unsigned nsecs,
u32 word, u8 bits,
unsigned flags),
unsigned ns,
struct spi_transfer *t,
unsigned flags
)
{
unsigned bits = t->bits_per_word;
unsigned count = t->len;
const u16 *tx = t->tx_buf;
u16 *rx = t->rx_buf;
while (likely(count > 1)) {
u16 word = 0;
if (tx)
word = *tx++;
word = txrx_word(spi, ns, word, bits, flags);
if (rx)
*rx++ = word;
count -= 2;
}
return t->len - count;
}
static unsigned bitbang_txrx_32(
struct spi_device *spi,
u32 (*txrx_word)(struct spi_device *spi,
unsigned nsecs,
u32 word, u8 bits,
unsigned flags),
unsigned ns,
struct spi_transfer *t,
unsigned flags
)
{
unsigned bits = t->bits_per_word;
unsigned count = t->len;
const u32 *tx = t->tx_buf;
u32 *rx = t->rx_buf;
while (likely(count > 3)) {
u32 word = 0;
if (tx)
word = *tx++;
word = txrx_word(spi, ns, word, bits, flags);
if (rx)
*rx++ = word;
count -= 4;
}
return t->len - count;
}
int spi_bitbang_setup_transfer(struct spi_device *spi, struct spi_transfer *t)
{
struct spi_bitbang_cs *cs = spi->controller_state;
u8 bits_per_word;
u32 hz;
if (t) {
bits_per_word = t->bits_per_word;
hz = t->speed_hz;
} else {
bits_per_word = 0;
hz = 0;
}
/* spi_transfer level calls that work per-word */
if (!bits_per_word)
bits_per_word = spi->bits_per_word;
if (bits_per_word <= 8)
cs->txrx_bufs = bitbang_txrx_8;
else if (bits_per_word <= 16)
cs->txrx_bufs = bitbang_txrx_16;
else if (bits_per_word <= 32)
cs->txrx_bufs = bitbang_txrx_32;
else
return -EINVAL;
/* nsecs = (clock period)/2 */
if (!hz)
hz = spi->max_speed_hz;
if (hz) {
cs->nsecs = (1000000000/2) / hz;
if (cs->nsecs > (MAX_UDELAY_MS * 1000 * 1000))
return -EINVAL;
}
return 0;
}
EXPORT_SYMBOL_GPL(spi_bitbang_setup_transfer);
/*
* spi_bitbang_setup - default setup for per-word I/O loops
*/
int spi_bitbang_setup(struct spi_device *spi)
{
struct spi_bitbang_cs *cs = spi->controller_state;
struct spi_bitbang *bitbang;
spi: Cleanup on failure of initial setup Commit c7299fea6769 ("spi: Fix spi device unregister flow") changed the SPI core's behavior if the ->setup() hook returns an error upon adding an spi_device: Before, the ->cleanup() hook was invoked to free any allocations that were made by ->setup(). With the commit, that's no longer the case, so the ->setup() hook is expected to free the allocations itself. I've identified 5 drivers which depend on the old behavior and am fixing them up hereinafter: spi-bitbang.c spi-fsl-spi.c spi-omap-uwire.c spi-omap2-mcspi.c spi-pxa2xx.c Importantly, ->setup() is not only invoked on spi_device *addition*: It may subsequently be called to *change* SPI parameters. If changing these SPI parameters fails, freeing memory allocations would be wrong. That should only be done if the spi_device is finally destroyed. I am therefore using a bool "initial_setup" in 4 of the affected drivers to differentiate between the invocation on *adding* the spi_device and any subsequent invocations: spi-bitbang.c spi-fsl-spi.c spi-omap-uwire.c spi-omap2-mcspi.c In spi-pxa2xx.c, it seems the ->setup() hook can only fail on spi_device addition, not any subsequent calls. It therefore doesn't need the bool. It's worth noting that 5 other drivers already perform a cleanup if the ->setup() hook fails. Before c7299fea6769, they caused a double-free if ->setup() failed on spi_device addition. Since the commit, they're fine. These drivers are: spi-mpc512x-psc.c spi-pl022.c spi-s3c64xx.c spi-st-ssc4.c spi-tegra114.c (spi-pxa2xx.c also already performs a cleanup, but only in one of several error paths.) Fixes: c7299fea6769 ("spi: Fix spi device unregister flow") Signed-off-by: Lukas Wunner <lukas@wunner.de> Cc: Saravana Kannan <saravanak@google.com> Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> # pxa2xx Link: https://lore.kernel.org/r/f76a0599469f265b69c371538794101fa37b5536.1622149321.git.lukas@wunner.de Signed-off-by: Mark Brown <broonie@kernel.org>
2021-05-27 21:10:56 +00:00
bool initial_setup = false;
int retval;
bitbang = spi_master_get_devdata(spi->master);
if (!cs) {
cs = kzalloc(sizeof(*cs), GFP_KERNEL);
if (!cs)
return -ENOMEM;
spi->controller_state = cs;
spi: Cleanup on failure of initial setup Commit c7299fea6769 ("spi: Fix spi device unregister flow") changed the SPI core's behavior if the ->setup() hook returns an error upon adding an spi_device: Before, the ->cleanup() hook was invoked to free any allocations that were made by ->setup(). With the commit, that's no longer the case, so the ->setup() hook is expected to free the allocations itself. I've identified 5 drivers which depend on the old behavior and am fixing them up hereinafter: spi-bitbang.c spi-fsl-spi.c spi-omap-uwire.c spi-omap2-mcspi.c spi-pxa2xx.c Importantly, ->setup() is not only invoked on spi_device *addition*: It may subsequently be called to *change* SPI parameters. If changing these SPI parameters fails, freeing memory allocations would be wrong. That should only be done if the spi_device is finally destroyed. I am therefore using a bool "initial_setup" in 4 of the affected drivers to differentiate between the invocation on *adding* the spi_device and any subsequent invocations: spi-bitbang.c spi-fsl-spi.c spi-omap-uwire.c spi-omap2-mcspi.c In spi-pxa2xx.c, it seems the ->setup() hook can only fail on spi_device addition, not any subsequent calls. It therefore doesn't need the bool. It's worth noting that 5 other drivers already perform a cleanup if the ->setup() hook fails. Before c7299fea6769, they caused a double-free if ->setup() failed on spi_device addition. Since the commit, they're fine. These drivers are: spi-mpc512x-psc.c spi-pl022.c spi-s3c64xx.c spi-st-ssc4.c spi-tegra114.c (spi-pxa2xx.c also already performs a cleanup, but only in one of several error paths.) Fixes: c7299fea6769 ("spi: Fix spi device unregister flow") Signed-off-by: Lukas Wunner <lukas@wunner.de> Cc: Saravana Kannan <saravanak@google.com> Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> # pxa2xx Link: https://lore.kernel.org/r/f76a0599469f265b69c371538794101fa37b5536.1622149321.git.lukas@wunner.de Signed-off-by: Mark Brown <broonie@kernel.org>
2021-05-27 21:10:56 +00:00
initial_setup = true;
}
/* per-word shift register access, in hardware or bitbanging */
cs->txrx_word = bitbang->txrx_word[spi->mode & (SPI_CPOL|SPI_CPHA)];
spi: Cleanup on failure of initial setup Commit c7299fea6769 ("spi: Fix spi device unregister flow") changed the SPI core's behavior if the ->setup() hook returns an error upon adding an spi_device: Before, the ->cleanup() hook was invoked to free any allocations that were made by ->setup(). With the commit, that's no longer the case, so the ->setup() hook is expected to free the allocations itself. I've identified 5 drivers which depend on the old behavior and am fixing them up hereinafter: spi-bitbang.c spi-fsl-spi.c spi-omap-uwire.c spi-omap2-mcspi.c spi-pxa2xx.c Importantly, ->setup() is not only invoked on spi_device *addition*: It may subsequently be called to *change* SPI parameters. If changing these SPI parameters fails, freeing memory allocations would be wrong. That should only be done if the spi_device is finally destroyed. I am therefore using a bool "initial_setup" in 4 of the affected drivers to differentiate between the invocation on *adding* the spi_device and any subsequent invocations: spi-bitbang.c spi-fsl-spi.c spi-omap-uwire.c spi-omap2-mcspi.c In spi-pxa2xx.c, it seems the ->setup() hook can only fail on spi_device addition, not any subsequent calls. It therefore doesn't need the bool. It's worth noting that 5 other drivers already perform a cleanup if the ->setup() hook fails. Before c7299fea6769, they caused a double-free if ->setup() failed on spi_device addition. Since the commit, they're fine. These drivers are: spi-mpc512x-psc.c spi-pl022.c spi-s3c64xx.c spi-st-ssc4.c spi-tegra114.c (spi-pxa2xx.c also already performs a cleanup, but only in one of several error paths.) Fixes: c7299fea6769 ("spi: Fix spi device unregister flow") Signed-off-by: Lukas Wunner <lukas@wunner.de> Cc: Saravana Kannan <saravanak@google.com> Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> # pxa2xx Link: https://lore.kernel.org/r/f76a0599469f265b69c371538794101fa37b5536.1622149321.git.lukas@wunner.de Signed-off-by: Mark Brown <broonie@kernel.org>
2021-05-27 21:10:56 +00:00
if (!cs->txrx_word) {
retval = -EINVAL;
goto err_free;
}
if (bitbang->setup_transfer) {
spi: Cleanup on failure of initial setup Commit c7299fea6769 ("spi: Fix spi device unregister flow") changed the SPI core's behavior if the ->setup() hook returns an error upon adding an spi_device: Before, the ->cleanup() hook was invoked to free any allocations that were made by ->setup(). With the commit, that's no longer the case, so the ->setup() hook is expected to free the allocations itself. I've identified 5 drivers which depend on the old behavior and am fixing them up hereinafter: spi-bitbang.c spi-fsl-spi.c spi-omap-uwire.c spi-omap2-mcspi.c spi-pxa2xx.c Importantly, ->setup() is not only invoked on spi_device *addition*: It may subsequently be called to *change* SPI parameters. If changing these SPI parameters fails, freeing memory allocations would be wrong. That should only be done if the spi_device is finally destroyed. I am therefore using a bool "initial_setup" in 4 of the affected drivers to differentiate between the invocation on *adding* the spi_device and any subsequent invocations: spi-bitbang.c spi-fsl-spi.c spi-omap-uwire.c spi-omap2-mcspi.c In spi-pxa2xx.c, it seems the ->setup() hook can only fail on spi_device addition, not any subsequent calls. It therefore doesn't need the bool. It's worth noting that 5 other drivers already perform a cleanup if the ->setup() hook fails. Before c7299fea6769, they caused a double-free if ->setup() failed on spi_device addition. Since the commit, they're fine. These drivers are: spi-mpc512x-psc.c spi-pl022.c spi-s3c64xx.c spi-st-ssc4.c spi-tegra114.c (spi-pxa2xx.c also already performs a cleanup, but only in one of several error paths.) Fixes: c7299fea6769 ("spi: Fix spi device unregister flow") Signed-off-by: Lukas Wunner <lukas@wunner.de> Cc: Saravana Kannan <saravanak@google.com> Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> # pxa2xx Link: https://lore.kernel.org/r/f76a0599469f265b69c371538794101fa37b5536.1622149321.git.lukas@wunner.de Signed-off-by: Mark Brown <broonie@kernel.org>
2021-05-27 21:10:56 +00:00
retval = bitbang->setup_transfer(spi, NULL);
if (retval < 0)
spi: Cleanup on failure of initial setup Commit c7299fea6769 ("spi: Fix spi device unregister flow") changed the SPI core's behavior if the ->setup() hook returns an error upon adding an spi_device: Before, the ->cleanup() hook was invoked to free any allocations that were made by ->setup(). With the commit, that's no longer the case, so the ->setup() hook is expected to free the allocations itself. I've identified 5 drivers which depend on the old behavior and am fixing them up hereinafter: spi-bitbang.c spi-fsl-spi.c spi-omap-uwire.c spi-omap2-mcspi.c spi-pxa2xx.c Importantly, ->setup() is not only invoked on spi_device *addition*: It may subsequently be called to *change* SPI parameters. If changing these SPI parameters fails, freeing memory allocations would be wrong. That should only be done if the spi_device is finally destroyed. I am therefore using a bool "initial_setup" in 4 of the affected drivers to differentiate between the invocation on *adding* the spi_device and any subsequent invocations: spi-bitbang.c spi-fsl-spi.c spi-omap-uwire.c spi-omap2-mcspi.c In spi-pxa2xx.c, it seems the ->setup() hook can only fail on spi_device addition, not any subsequent calls. It therefore doesn't need the bool. It's worth noting that 5 other drivers already perform a cleanup if the ->setup() hook fails. Before c7299fea6769, they caused a double-free if ->setup() failed on spi_device addition. Since the commit, they're fine. These drivers are: spi-mpc512x-psc.c spi-pl022.c spi-s3c64xx.c spi-st-ssc4.c spi-tegra114.c (spi-pxa2xx.c also already performs a cleanup, but only in one of several error paths.) Fixes: c7299fea6769 ("spi: Fix spi device unregister flow") Signed-off-by: Lukas Wunner <lukas@wunner.de> Cc: Saravana Kannan <saravanak@google.com> Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> # pxa2xx Link: https://lore.kernel.org/r/f76a0599469f265b69c371538794101fa37b5536.1622149321.git.lukas@wunner.de Signed-off-by: Mark Brown <broonie@kernel.org>
2021-05-27 21:10:56 +00:00
goto err_free;
}
dev_dbg(&spi->dev, "%s, %u nsec/bit\n", __func__, 2 * cs->nsecs);
return 0;
spi: Cleanup on failure of initial setup Commit c7299fea6769 ("spi: Fix spi device unregister flow") changed the SPI core's behavior if the ->setup() hook returns an error upon adding an spi_device: Before, the ->cleanup() hook was invoked to free any allocations that were made by ->setup(). With the commit, that's no longer the case, so the ->setup() hook is expected to free the allocations itself. I've identified 5 drivers which depend on the old behavior and am fixing them up hereinafter: spi-bitbang.c spi-fsl-spi.c spi-omap-uwire.c spi-omap2-mcspi.c spi-pxa2xx.c Importantly, ->setup() is not only invoked on spi_device *addition*: It may subsequently be called to *change* SPI parameters. If changing these SPI parameters fails, freeing memory allocations would be wrong. That should only be done if the spi_device is finally destroyed. I am therefore using a bool "initial_setup" in 4 of the affected drivers to differentiate between the invocation on *adding* the spi_device and any subsequent invocations: spi-bitbang.c spi-fsl-spi.c spi-omap-uwire.c spi-omap2-mcspi.c In spi-pxa2xx.c, it seems the ->setup() hook can only fail on spi_device addition, not any subsequent calls. It therefore doesn't need the bool. It's worth noting that 5 other drivers already perform a cleanup if the ->setup() hook fails. Before c7299fea6769, they caused a double-free if ->setup() failed on spi_device addition. Since the commit, they're fine. These drivers are: spi-mpc512x-psc.c spi-pl022.c spi-s3c64xx.c spi-st-ssc4.c spi-tegra114.c (spi-pxa2xx.c also already performs a cleanup, but only in one of several error paths.) Fixes: c7299fea6769 ("spi: Fix spi device unregister flow") Signed-off-by: Lukas Wunner <lukas@wunner.de> Cc: Saravana Kannan <saravanak@google.com> Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> # pxa2xx Link: https://lore.kernel.org/r/f76a0599469f265b69c371538794101fa37b5536.1622149321.git.lukas@wunner.de Signed-off-by: Mark Brown <broonie@kernel.org>
2021-05-27 21:10:56 +00:00
err_free:
if (initial_setup)
kfree(cs);
return retval;
}
EXPORT_SYMBOL_GPL(spi_bitbang_setup);
/*
* spi_bitbang_cleanup - default cleanup for per-word I/O loops
*/
void spi_bitbang_cleanup(struct spi_device *spi)
{
kfree(spi->controller_state);
}
EXPORT_SYMBOL_GPL(spi_bitbang_cleanup);
static int spi_bitbang_bufs(struct spi_device *spi, struct spi_transfer *t)
{
struct spi_bitbang_cs *cs = spi->controller_state;
unsigned nsecs = cs->nsecs;
struct spi_bitbang *bitbang;
bitbang = spi_master_get_devdata(spi->master);
if (bitbang->set_line_direction) {
int err;
err = bitbang->set_line_direction(spi, !!(t->tx_buf));
if (err < 0)
return err;
}
if (spi->mode & SPI_3WIRE) {
unsigned flags;
flags = t->tx_buf ? SPI_MASTER_NO_RX : SPI_MASTER_NO_TX;
return cs->txrx_bufs(spi, cs->txrx_word, nsecs, t, flags);
}
return cs->txrx_bufs(spi, cs->txrx_word, nsecs, t, 0);
}
/*----------------------------------------------------------------------*/
/*
* SECOND PART ... simple transfer queue runner.
*
* This costs a task context per controller, running the queue by
* performing each transfer in sequence. Smarter hardware can queue
* several DMA transfers at once, and process several controller queues
* in parallel; this driver doesn't match such hardware very well.
*
* Drivers can provide word-at-a-time i/o primitives, or provide
* transfer-at-a-time ones to leverage dma or fifo hardware.
*/
static int spi_bitbang_prepare_hardware(struct spi_master *spi)
{
struct spi_bitbang *bitbang;
bitbang = spi_master_get_devdata(spi);
mutex_lock(&bitbang->lock);
bitbang->busy = 1;
mutex_unlock(&bitbang->lock);
return 0;
}
static int spi_bitbang_transfer_one(struct spi_master *master,
struct spi_device *spi,
struct spi_transfer *transfer)
{
struct spi_bitbang *bitbang = spi_master_get_devdata(master);
int status = 0;
if (bitbang->setup_transfer) {
status = bitbang->setup_transfer(spi, transfer);
if (status < 0)
goto out;
}
if (transfer->len)
status = bitbang->txrx_bufs(spi, transfer);
if (status == transfer->len)
status = 0;
else if (status >= 0)
status = -EREMOTEIO;
out:
spi_finalize_current_transfer(master);
return status;
}
static int spi_bitbang_unprepare_hardware(struct spi_master *spi)
{
struct spi_bitbang *bitbang;
bitbang = spi_master_get_devdata(spi);
mutex_lock(&bitbang->lock);
bitbang->busy = 0;
mutex_unlock(&bitbang->lock);
return 0;
}
static void spi_bitbang_set_cs(struct spi_device *spi, bool enable)
{
struct spi_bitbang *bitbang = spi_master_get_devdata(spi->master);
/* SPI core provides CS high / low, but bitbang driver
* expects CS active
* spi device driver takes care of handling SPI_CS_HIGH
*/
enable = (!!(spi->mode & SPI_CS_HIGH) == enable);
ndelay(SPI_BITBANG_CS_DELAY);
bitbang->chipselect(spi, enable ? BITBANG_CS_ACTIVE :
BITBANG_CS_INACTIVE);
ndelay(SPI_BITBANG_CS_DELAY);
}
/*----------------------------------------------------------------------*/
int spi_bitbang_init(struct spi_bitbang *bitbang)
{
struct spi_master *master = bitbang->master;
bool custom_cs;
if (!master)
return -EINVAL;
/*
* We only need the chipselect callback if we are actually using it.
* If we just use GPIO descriptors, it is surplus. If the
* SPI_MASTER_GPIO_SS flag is set, we always need to call the
* driver-specific chipselect routine.
*/
custom_cs = (!master->use_gpio_descriptors ||
(master->flags & SPI_MASTER_GPIO_SS));
if (custom_cs && !bitbang->chipselect)
return -EINVAL;
mutex_init(&bitbang->lock);
if (!master->mode_bits)
master->mode_bits = SPI_CPOL | SPI_CPHA | bitbang->flags;
if (master->transfer || master->transfer_one_message)
return -EINVAL;
master->prepare_transfer_hardware = spi_bitbang_prepare_hardware;
master->unprepare_transfer_hardware = spi_bitbang_unprepare_hardware;
master->transfer_one = spi_bitbang_transfer_one;
/*
* When using GPIO descriptors, the ->set_cs() callback doesn't even
* get called unless SPI_MASTER_GPIO_SS is set.
*/
if (custom_cs)
master->set_cs = spi_bitbang_set_cs;
if (!bitbang->txrx_bufs) {
bitbang->use_dma = 0;
bitbang->txrx_bufs = spi_bitbang_bufs;
if (!master->setup) {
if (!bitbang->setup_transfer)
bitbang->setup_transfer =
spi_bitbang_setup_transfer;
master->setup = spi_bitbang_setup;
master->cleanup = spi_bitbang_cleanup;
}
}
return 0;
}
EXPORT_SYMBOL_GPL(spi_bitbang_init);
/**
* spi_bitbang_start - start up a polled/bitbanging SPI master driver
* @bitbang: driver handle
*
* Caller should have zero-initialized all parts of the structure, and then
* provided callbacks for chip selection and I/O loops. If the master has
* a transfer method, its final step should call spi_bitbang_transfer; or,
* that's the default if the transfer routine is not initialized. It should
* also set up the bus number and number of chipselects.
*
* For i/o loops, provide callbacks either per-word (for bitbanging, or for
* hardware that basically exposes a shift register) or per-spi_transfer
* (which takes better advantage of hardware like fifos or DMA engines).
*
* Drivers using per-word I/O loops should use (or call) spi_bitbang_setup,
* spi_bitbang_cleanup and spi_bitbang_setup_transfer to handle those spi
* master methods. Those methods are the defaults if the bitbang->txrx_bufs
* routine isn't initialized.
*
* This routine registers the spi_master, which will process requests in a
* dedicated task, keeping IRQs unblocked most of the time. To stop
* processing those requests, call spi_bitbang_stop().
*
* On success, this routine will take a reference to master. The caller is
* responsible for calling spi_bitbang_stop() to decrement the reference and
* spi_master_put() as counterpart of spi_alloc_master() to prevent a memory
* leak.
*/
int spi_bitbang_start(struct spi_bitbang *bitbang)
{
struct spi_master *master = bitbang->master;
int ret;
ret = spi_bitbang_init(bitbang);
if (ret)
return ret;
/* driver may get busy before register() returns, especially
* if someone registered boardinfo for devices
*/
ret = spi_register_master(spi_master_get(master));
if (ret)
spi_master_put(master);
spi: bitbang: Fix NULL pointer dereference in spi_unregister_master If spi_register_master fails in spi_bitbang_start because device_add failure, We should return the error code other than 0, otherwise calling spi_bitbang_stop may trigger NULL pointer dereference like this: BUG: KASAN: null-ptr-deref in __list_del_entry_valid+0x45/0xd0 Read of size 8 at addr 0000000000000000 by task syz-executor.0/3661 CPU: 0 PID: 3661 Comm: syz-executor.0 Not tainted 5.1.0+ #28 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014 Call Trace: dump_stack+0xa9/0x10e ? __list_del_entry_valid+0x45/0xd0 ? __list_del_entry_valid+0x45/0xd0 __kasan_report+0x171/0x18d ? __list_del_entry_valid+0x45/0xd0 kasan_report+0xe/0x20 __list_del_entry_valid+0x45/0xd0 spi_unregister_controller+0x99/0x1b0 spi_lm70llp_attach+0x3ae/0x4b0 [spi_lm70llp] ? 0xffffffffc1128000 ? klist_next+0x131/0x1e0 ? driver_detach+0x40/0x40 [parport] port_check+0x3b/0x50 [parport] bus_for_each_dev+0x115/0x180 ? subsys_dev_iter_exit+0x20/0x20 __parport_register_driver+0x1f0/0x210 [parport] ? 0xffffffffc1150000 do_one_initcall+0xb9/0x3b5 ? perf_trace_initcall_level+0x270/0x270 ? kasan_unpoison_shadow+0x30/0x40 ? kasan_unpoison_shadow+0x30/0x40 do_init_module+0xe0/0x330 load_module+0x38eb/0x4270 ? module_frob_arch_sections+0x20/0x20 ? kernel_read_file+0x188/0x3f0 ? find_held_lock+0x6d/0xd0 ? fput_many+0x1a/0xe0 ? __do_sys_finit_module+0x162/0x190 __do_sys_finit_module+0x162/0x190 ? __ia32_sys_init_module+0x40/0x40 ? __mutex_unlock_slowpath+0xb4/0x3f0 ? wait_for_completion+0x240/0x240 ? vfs_write+0x160/0x2a0 ? lockdep_hardirqs_off+0xb5/0x100 ? mark_held_locks+0x1a/0x90 ? do_syscall_64+0x14/0x2a0 do_syscall_64+0x72/0x2a0 entry_SYSCALL_64_after_hwframe+0x49/0xbe Reported-by: Hulk Robot <hulkci@huawei.com> Fixes: 702a4879ec33 ("spi: bitbang: Let spi_bitbang_start() take a reference to master") Signed-off-by: YueHaibing <yuehaibing@huawei.com> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> Reviewed-by: Axel Lin <axel.lin@ingics.com> Reviewed-by: Mukesh Ojha <mojha@codeaurora.org> Signed-off-by: Mark Brown <broonie@kernel.org>
2019-05-16 07:56:56 +00:00
return ret;
}
EXPORT_SYMBOL_GPL(spi_bitbang_start);
/*
* spi_bitbang_stop - stops the task providing spi communication
*/
void spi_bitbang_stop(struct spi_bitbang *bitbang)
{
spi_unregister_master(bitbang->master);
}
EXPORT_SYMBOL_GPL(spi_bitbang_stop);
MODULE_LICENSE("GPL");